Manufacture of artificial silk, artificial horsehair and like products



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Patented June 28, .1932

PATENT; OFF CE HENRY D BEYFUS, OF LONDON, ENGLAND murac'ruan oran-nrrcmr. SILK, anrrrrcm HOBSEHAIR AND 1.11m rnonuc'rs Iio Drawing.Original applloatlon flled June 28,1923, Serial No. 648,350, and inGreat Britain August 11, 1922. Divided and this application filed April5, 1928., Serial No. 267,808.

This application is a divisional application from my U. S. applicationSerial No. 648,350 which eventuated. into Patent No.

1,688,531, granted October 23, 1928.

This invention relates to the manufacture of artificial silk, artificialhorsehair or like threads or filaments from, solutions of celluloseacetate in particular, but applies also to their production from othersolutions of esters of cellulose or of ethers of cellulose such forexample as ethyl-, methylor benzyl cellulose, or from mixtures of any ofsuch cellulose derivatives, all of which cellulose derivatives arehereinafter in the claims referred to as organic substitutionderivatives of cellulose. The invention solely concerns processes inwhich the artificial threads or filaments are produced by the dry orevaporative method of formation, that is to say by so extruding asolution of the cellulose derivative or derivatives inror containing avolatile or vaporizable solvent or solvents, through jets or spinneretsinto a heated or other atmosphere in which the filaments or threadssolidify by evaporation of solvent. In particular the invention relatesto the manufacture of threads, filaments or the like from celluloseacetate solutions by dry or evaporative spinning;

Inthe manufacture of artificial threads or filaments from solutions ofcellulose acetate or other cellulose esters or ethers such as re-\ferred to'by the evaporative method it is usual to employ spinningsolutions of rela? tively low concentration, containing not more thanabout 16% of the cellulose derivative or derivatives in the solvent 0solvents used. It has now been found that y employing for the d orevaporative spinning solu or the like from cellulose acetate solutions,for

tions of su stantially higher concentrations, containing more than 20%of the cellulose derivative or derivatives, and especially in the caseof cellulose acetate solutions, artificial threads or filaments ofimproved quality can be obtained, possessingrg'reatermechanical strengthand rounder section, 'and showin much less tendency to crinkle or turnwooll in appearance under the action of very liot or boiling water, thanis the case with dry-spun artificial threads or filaments, made from theless concentrated solutions previously employed. It is moreover foundthat, especially in the case of cel lulose acetate, the employment ofsolutions of high concentrations as referred to has the furtheradvantage of obviating or greatly reducing what may be called glitter ofthe threads, filaments or the like, that is to say, a glittering orscintillating efi'ect which is sometimes possessed by filaments orthreads formed by dry 'or evaporative spinning from solutions of therelatively low concentration usually employed, and possibly due to thesectional configuration of the filaments resulting from the spinning ofsuch solutions, by the dry or evaporative method of formation. Thisglitter effect or glitter-producing structure of the filaments or thelike can in some cases be adisadvantage. For example, in cases wheregoods in hank, .79 woven or knitted fabric or other form, made withthreads showing such glitter effect are dyed in black or dark colours,it is sometimes found that the dyed goods give an impression as if theartificial silk is dyed only partially or not deep enough or that theyhave a worn appearance, this being more especially seen in fabrics. Eachper cent increase in the, concentration of the solutions of thecellulose acetate or other cellulose derivatives over and above 20% isaccompanied by a great increase in the viscosity of thespinningsolutions and in the strengthof the filaments or threads obtained.Moreover, at a concentration of about 21%, glitterless filaments areobtainable. At a concentration of 22% theroundness and strength of thefilaments is still more marked.

By forming the dry spun threads, filaments example, of highconcentrations such as before referred to, namely 21 or 22 to 25%, itwill be seen that the filaments or threads are stronger than those madefrom solutions of the usual low concentrations, not so liable to crinkleor. turn woolly as a result of the action of hot water, and moreoverthat glitter or glitter-producing structure is obviated or greatlyreduced, with its tendenc to give on dyed goods, and especially goods dyed in black or dark colours, the appearance before referred to.

The following are two examples of spinning solutions which may beemployed according to the invention, it being understood that these aregiven only by way of illustration and that other solvents or solventmixtures may be employed and that the concentrations can be variedwithout departing from the invention.

- E wample' 1 Cellulose acetate is dissolved inacetone in quantity togive a solution. containing between 21 and 25% cellulose acetate.

Ewample 2- Cellulose acetate is dissolved in acetone containing about 5to 10% of alcohol and about 5% of water, in a quantity to give asolution containing between 22 and 25% of cellulose acetate in thesolvent mixture.

The solutions are dry spun inthe known 'way by extrusion throughspinnerets into a heated atmosphere;

While my invention relates especially to the manufacture of artificialthreads, filaments or the like from cellulose acetate solutions by thedry or evaporative method it is also applicable to their production bythe dry or evaporative method from solutions of other cellulose estersor ethers or mixtures of cellulose esters or/and ethers. v

What I claim and desire to secure by Let ters Patent is 1. Process forthe manufacture of artificial filaments and threads, characterized inthat the same are dry spun from con'centratedsolutions of organicsubstitution derivatives of cellulose containing at least 21 and lessthan 25% of the cellulose derivative.

2. Process for the manufacture of artificial filaments and threads,characterized in that the same are dry spunfrom concentrated solution oforganic substitution derivatives of cellulose containing at least 22 andless than 25% of-the cellulose derivative.

3. Process for the manufacture of artificial filaments and threads,characterized in that same are dry spun from concentrated solutions ofcellulose acetate containing at least 21 and less than 25% of celluloseacetate.

4. Process for the manufacture of artificial filaments and threads,characterized in that the same are dry spun from concentrated solutions.of cellulose acetate containing at least 22 and less than 25% ofcellulose acetate.

, In testimony whereof I have scribed my name.

HENRY DREYFUS.

hereunto sub-

